I know Warren is the SME on this area but I just wanted to say I have had success splitting the K2, using one PCIe slot as direct and the other as shared. The shared is less than stellar on the performance, the direct was pretty good for 3d models. I even shot a video of me doing direct on youtube.
NVIDIA K2 on VMware View running Solidworks - YouTube
Right now I'm playing around with the Q4000 trying to get direct to work and having more issues than I did getting K2 to work in the direct mode